tdb performance

[Andrew Bartlett]

Michael Still wrote:
> 
> On Sun, 27 Jan 2002, Andrew Bartlett wrote:
> 
> > Snapshotting seems to be the traditional method.  It think the idea is
> > that tdb is sufficiently small that keeping it statically linked is not
> > too large a burden.  I know its just in the 'tdb' subdir of Samba HEAD,
> > Samba 2.2 and Samba TNG.
> 
> Cool. Done.
> 
> > I think this is an offer that will be taken up, but you will have to
> > find somebody who works on tdb (I don't).
> 
> Can I have a hint?

See who replies to this e-mail...

> > A memory mapped file is not sufficiently cached?  By doing it this way
> > the underlying OS should have slight chance of getting it cached.
> 
> I am not aware of memory mapped files in tdb. The most recent version of
> the code I had until the other day was like a year old, so perhaps it is
> newer than that. I can't find in my quick reading of the code a reference
> to it in tdb_open().

TDB is mmaped by default.  It can be truned off by an flag on open, as
it is on some 'blacklisted' OSs.  See tdb/tdbutil.c

> I would love to be able to open a memory only tdb. Can I have a hint?